Depression is a miserable lying bastard. When you are in its throes, every perceived slight is used to further the argument that you are a worthless waste of oxygen and the world is better off without you.
The logical part of your brain, and the person who you are, knows that this is bullshit.
But, in the throes of a depressive episode when you get knocked back by a trivial illness it becomes a big deal…proof that you are nothing, have done nothing…are worthless.
At times like these there are two important thing to remember is that it gets better and that depression is a fucking miserable liar. And misery loves company.